The winner of the draw will receive a “co-pilot” place on the two-seat craft being built by Californian firm XCOR at its base in the Mojave desert.

XCOR hopes to be ready for test flights by early next year with ex-Nasa shuttle commander Rick Searfoss — the 301st person into space — as pilot. A ticket on the 30ft-long Lynx, which is expected to be ready to fly by the end of next year, would usually cost at least $95,000 (£59,000). The prize also includes £5,000 from National Lottery operator Camelot to cover the costs of preparing for the trip.

The Lynx, which has four rocket engines, takes off and lands from a runway but climbs almost vertically shortly after take-off.

Andrew Nelson, XCOR’s chief operating officer, said passengers would experience G-forces similar to that on a rollercoaster but promised a “smooth ride”. “You’re flying in the right seat, so we will be asking people to help out the pilot during the launch, monitoring the video feeds of the rocket plume and work the radio,” he said.

“It’s a real astronaut experience, we want you to help out during the flight. You’re the co-pilot basically, it’s a ‘Right Stuff’ experience — we think it will be a hell of a ride.”

The winner will be given a full medical examination before beginning training sessions over a long weekend at the company’s base, with tuition about how the Lynx works and G-force training in test aircraft.

On the morning of the flight, the winner will be briefed about the mission before putting on a spacesuit.

“We think that will really focus people,” said Nelson. “After you’re strapped in and given a final thumbs-up, we tow the craft to the runway and boom — there’s a kick in the pants when we fire the engines. It’s a steep acceleration curve, and you effectively turn into a rocket. Then you’ll accelerate, and after 60 seconds pass the sound barrier.

“At 200,000 feet, the engines cut out and you’re looking into space. Look over your shoulder and you see the curvature of the Earth and feel weightlessness. We can even point the vehicle to show you anywhere you want to see.”

The flight will be recorded on on-board HD cameras and after six or seven minutes, the Lynx will be realigned before gliding back to Earth.